Casting mold apparatus

ABSTRACT

Apparatus from which the sides of a confined area mold can be assembled to contain a liquid or semiliquid substance for casting purposes or for other applications. One or more strips of material having a predetermined characteristic, such as the grain structure of wood, are provided with a number of spaced grooves transversely aligned relative to the characteristic of the structure on both sides thereof, and at staggered intervals. The strips are readily manually breakable along any of the grooves to provide a tongue end which is insertable within another of the grooves on a separate strip. A number of strip segments can thus be joined together in tongue-and-groove fashion to enclose an area containing a feature such as a footprint, of which a casting impression is desired to be made, thereby to provide a portable substantially leakproof casting mold which can be readily assembled from material which is compact and easily transportable.

ilnited States Patent 1191 Arps CASTING MOLD APPARATUS [76] Inventor: Hilbert Arps, 1306 Piedmont Ave.,

' Atlanta, Ga. 30309 [56] References Cited UNITED STATES PATENTS 1,512,905 10/1924 Bunker ..249/168 D200,264 2/1965 Tudor ..220/22 Primary Examiner-J. Spencer Overholser Assistant Examiner-DeWalden W. Jones Attorney, Agent, or Firm-Jones, Thomas & Askew Jan. 29, 1974 57 ABSTRACT Apparatus from which the sides of a confined area mold can be assembled to contain a liquid or semiliquid substance for casting purposes or for other applications. One or more strips of material having a predetermined characteristic, such as the grain structure of wood, are provided with a number of spaced grooves transversely aligned relative to the characteristic of the structure on both sides thereof, and at staggered intervals. The strips are readily manually breakable along any of the grooves to provide a tongue end which is insertable within another of the grooves on a separate strip. A number of strip segments can thus be joined together in tongue-and-groove fashion to enclose an area containing a feature such as a footprint, of which a casting impression is desired to be made, thereby to provide a portable substantially leakproof casting mold which can be readily assembled from material which is compact and easily transportable.

4 Claims, 8 Drawing Figures This invention relates in general to mold apparatus and in particular to prefabricated apparatus for assembling a mold.

In the investigation of a crime or suspected criminal activity, it is often necessary to obtain plaster casts of possible evidence such as impressions of tire tracks, shoe heel prints, and other markings which may have become impressed in the earth or in other soft material. This may be conventionally accomplished by mixing a quantity of material such as plaster of Paris or another suitable casting material, providing a form around the impression to be molded, pouring the casting material into the area defined by the form, and then removing the cast after the material has hardened. The casting, which is then removed from the earth or other surface on which the impression was found, can bear a striking similarity to the original impression and provides permanent evidence of an impression which may be washed away with the next rainstorm or otherwise soon obliterated.

The foregoing well-known and straightforward steps for obtaining plaster casts of such impressions can become complicated in actual practice because of the need to confine the casting material to the immediate area surrounding the impression. Plaster of Paris, the casting material most frequently used in police work, has the consistency of light cream when poured into the mold, and this material readily seeps out of even small cracks or gaps in the sides of a mold. Prior art attempts to overcome this problem have involved such makeshift expedients as the use of venetian blind slats to define a molding area around the impression. Such prior art expedients at best afford inadequate retention of the casting material, and these deficiencies become greatly magnified when used in typical field situations involving impressions foundin terrain which seldom presents ideal slope and other characteristics for making plaster molds.

Accordingly, it is an object of the present invention to provide an improved casting mold apparatus.

It is another object of the present invention to provide mold apparatus for casting impressions found on the ground.

It is still another object of the present invention to provide mold apparatus which is particularly useful for making plaster casts of impressions such as tire tracks, footprints, or the like.

It is a further object of the'present invention to provide casting mold apparatus which can be readily assembled to provide a mold having a number of possible configurations. Y

Other objects and many of the attendant advantages of the present invention will become more readily apparent from the following described embodiment thereof, including the .attached drawing, in which:

FIG. 1 shows a typical mold assembled from apparatus according to a disclosed embodiment of the present invention;

FIG. 2 shows an elevation view of a mold forming strip according to the disclosed embodiment;

FIG. 3 shows a plan view -of the mold forming strip of FIG. 2;

FIG. 4 shows a joining clip for connecting segments of the mold forming strips;

FIG. 5 shows an embodiment of an anchor pin used for retaining a mold according to the present invention;

FIG. 6 is an exploded view showing two segments of mold forming strip to be connected using the joining clip of FIG. 4;

FIG. 7 is an isometric view showing a mold forming strip as in FIGS. 2 and 3 being broken into two separate segments to form separate tongue ends; and

FIG. 8 shows a pair of separate mold forming strip segments being joined together.

Stated in general terms, the present invention provides a mold forming strip which may be of indeterminate length and which contains a number of grooves preferably along both sides thereof to enable desired mold forming segments to be broken from one or more of the mold strips. Each of the segments, as broken away, provides a tongue which can readily be joined with the grooves of an abutting strip segment in a tongue-and-groove manner, thereby readily enabling a series of such mold forming strip segments to be assembled in upright fashion around the perimeter of an area containing an impressiondesired to be cast. Provision is made for joining together two or more segments as needed, and for anchoring the strip segments against unwanted movement.

More specifically and with reference taken to FIGS. 2, 3, and 7, there is shown generally at 10 a mold forming strip according to an embodiment of the present invention and including an elongate strip 11 of a suitable material such as woood or the like and having a number of grooves 12 cut or otherwise disposed in the strip substantially perpendicular to the length of the strip. In the case of a strip 11 made of wood as shown in the disclosed embodiment, it can be seen that the length dimension of the strip is selected so that the grain 13 of the wood is substantially parallel to such length dimension.

The grooves 12 on one side of the strip 11 and the grooves 14 on the other side thereof are positioned at intervals staggered with'respect of each other, to promote .breaking of the strips for obtaining strip segments, as described more fully below. In a specific embodiment of the present invention, a number of strips 11 are cut from reasonably straight grained wood to have a width dimension 15 of about 1 inch and to have a thickness across the sides of about one-eighth inch. Plural grooves 12 and 14 are cut about every one-half inch along each side of the strip. Certain of the groove dimensions are important to the proper operation of the present invention, and in particular the grooves should be cut to a depth about one-half the thickness of the strip to facilitateproper breakage of the strips. Each of the grooves also preferably should have a width 16 at least one-half the thickness of the strip to accept the tongues of strip segments, as explained below.

It can be seen that a person who grasps a strip 11 in his hands and attempts to break the strip into shorter segments will invariably cause strip breakage to occur along a plane 20 shown in FIG. 7, which is defined by the mid-thickness of the strip interconnecting the ends of the adjacent staggered grooves 21 and 22, this plane of strip breakage being facilitated by the aforementioned alignment of the wood grain 13. It can also be seen that strip breakage as at 20 provides a pair of tongue ends 23 and 24 on each of the broken-away strip segments. It can be seen as in FIG. 8 that each of the tongues 23 and 24 is approximately one-half the width of the overall thickness of the strip 1 l, and so either tongues accordingly will readily fit within any of the grooves 12 or 14 on a segment of strip 11.

Considering the disclosed embodiment of the present invention as used in an actual plaster casting application, FIG. 1 shows an exemplary impression 30 which is imposed in a surrounding surface 31 which may be the ground, and which is desired to be cast. Once the person who is performing the casting operation has determined the desired outline of the cast, he provides a number of casting mold segments 32, 33, 34 and 35 simply by breaking such segments out of one or more available strips 11. Each of the broken-away mold segments 3235 has a pair of tongue ends, and it can be seen from FIG. 1 that the tongue ends on mold segments 32 and 34, for example, are snugly received within abutting grooves of the overlaping end of mold segments 33 and 35. Regardless of where the strip 11 is broken to provide the desired mold segments, the tongue provided by the broken end will be substantially formed by straight, parallel sides which fit into any of the grooves at substantially a right angle thereto for defining a mold corner which is effectively sealed to prevent the liquid or semiliquid casting material from escaping the mold.

If it is desired to anchor or otherwise retain the mold 36 provided by the mold segments 32-35, there can be provided one or more anchor ends 37 shown in FIGS. 1 and 5, made of wire or other suitable material to have an anchor portion 38 substantially longer than the width of the mold segment,to extend downwardly into the ground or other permeable surface, and a strip retaining end 39 which is bent or folded back along a length of the anchor portionto form a loop. The material of the anchor end 37 preferably is a wire or other member which is sufficiently thin to fit into the grooves on the strip, thereby holding the strip firmly in place on the surface 31. A number of anchor ends 37 are shown in FIG. 1 to hold a mold securely in place.

Where it is desired to make a mold of a relatively large or elongated impression, or where the segments of strip 11 available for forming a mold are too short to provide the desired length of a mold segment a joining clip 40 may be provided to frictionally fit over and retain together a pair of separate strip segments 41 and 42, as shown in FIG. 6. It will be appreciated that strip segments such as 41 and 42 may be segments which remain after other portions of an available strip 11 have already been broken off and used elsewhere for mold forming. The joining clip 40 may simply comprise a strip of metal which is folded back against itself to provide a resilient or springy clip having a nominal spacing 43 between clip sides which is somewhat less than the thickness of the aligned tongues 44 and 45 of the strip segments 41 and 42.

Although the disclosed embodiment of the present invention uses strips 11 made of wood, it will be appreciated that any suitable substitute material can be used in the present invention so long as such material can be dependably broken as described above for separation along a line to provide the tongues or functionally similar structural elements which are required to join the segments together as described herein. Thus, it will be understood that use of the tenn "grain" to describe particular structural orientation or alignment of the strips 11 is used herein not as a limitation of the present invention to strips made only from wood, but is instead used in reference to any arrangement of fibrous, crystalline, or other structural characteristic of the strip material which provides consistent characteristics of material breaking or cleavage as described herein.

It will be understood that the foregoing relates to a disclosed embodiment of the present invention and that numerous alterations or modifications may be made therein without departing from the spirit and the scope of the appended claims.

I claim:

1. Casting mold apparatus comprising:

an elongate strip of mold wall member made of a material having a grain structure which defines a certain region of cleavage of said material generally aligned with the length of said strip and which extends substantially along a plane which is proximately parallel to the length of said strip and contiguous with the inner surfaces defining the bottoms of said grooves, so that the planar grain structure defines said region of cleavage;

said strip of mold member material having a generally uniform thickness separating first and second sides thereof;

a plurality of grooves disposed in both of said first and second sides and extending substantially transversely of the length of said strip, said grooves on the first side being at locations which are offset along said strip length with respect to the locations of said grooves on the second side,

so that each of said grooves comprises a structurally weakened region extending transversely of said strip length and in certain selectively breakable alignment with said region of cleavage;

each of said grooves having a depth approximately one-half of said thickness of the material, and each of said grooves terminating at an inner surface substantially aligned with said certain region of cleavage; and

each of said grooves having a width at least approximately one-half of said thickness of the material.

2. Apparatus as in claim 1, further comprising at least one mold strip anchor member having means to engage and be retained in one of said grooves and additionally having an elongate anchor portion for insertion into an impressionable surface on which the casting mold apparatus is being used.

3. Apparatus as in claim 1, wherein:

said material is a fibrous material having a grain structure aligned generally parallel to said length of said strip.

4. Apparatus as in claim 1, wherein:

said material is a strip of fibrous material having a grain structure aligned along a plane generally parallel to the length of said strip and being sufficiently thin to be manually breakable along a line of cleavage comprising said plane extending between two adjacent grooves, and each of said grooves has an inner surface substantially aligned with a plane of said grain structure. 

1. Casting mold apparatus comprising: an elongate strip of mold wall member made of a material having a grain structure which defines a certain region of cleavage of said material generally aligned with the length of said strip and which extends substantially along a plane which is proximately parallel to the length of said strip and contiguous with the inner surfaces defining the bottoms of said grooves, so that the planar grain structure defines said region of cleavage; said strip of mold member material having a generally uniform thickness separating first and second sides thereof; a plurality of grooves disposed in both of said first and second sides and extending substantially transversely of the length of said strip, said grooves on the first side being at locations which are offset along said strip length with respect to the locations of said grooves on the second side, so that each of said grooves comprises a structurally weakened region extending transversely of said strip length and in certain selectively breakable alignment with said region of cleavage; each of said grooves having a depth approximately one-half of said thickness of the material, and each of said grooves terminating at an inner surface substantially aligned with said certain region of cleavage; and each of said grooves having a width at least approximately onehalf of said thickness of the material.
 2. Apparatus as in claim 1, further comprising at least one mold strip anchor member having means to engage and be retained in one of said grooves and additionally having an elongate anchor portion for insertion into an impressionable surface on which the casting mold apparatus is being used.
 3. Apparatus as in claim 1, wherein: said material is a fibrous material having a grain structure aligned generally parallel to said length of said strip.
 4. Apparatus as in claim 1, wherein: said material is a strip of fibrous material having a grain structure aligned along a plane generally parallel to the length of said strip and being sufficiently thin to be manually breakable along a line of cleavage comprising said plane extending between two adjacent grooves, and each of said grooves has an inner surface substantially aligned with a plane of said grain structure. 